It’s An Audio Distortion Analyzer, Just Not The One You Were Hoping For

An audio distortion analyzer is a specialist piece of analogue test equipment that usually costs a lot of money and can be hard to track down on the second hand market. Finding one is a moment of luck for the average engineer then, but [Thomas Scherrer OZ2CPU]’s discovery isn’t quite what he might have hoped for. Nonetheless, his Bang and Olufsen K3 Distortion meter DM1 from 1979 is still an interesting and high quality piece of test equipment, and the video below the break makes for a worthwhile watch.

Bang and Olufsen are best known for high-end design Hi-Fi units, thus it’s a surprise to find that in the past they also manufactured test equipment. This distortion meter isn’t a general purpose one, instead it’s designed to measure tape recorders in particular, and it uses an elegant technique. Instead of injecting a sine wave and removing it from what comes out in order to measure the products of the distortion, it records a 333 Hz sine wave onto a tape, then measures the strength of its 3rd harmonic at 1 kHz as an indication of distortion. It’s a working distortion meter made with clever analogue circuitry for a fraction of the cost of the more conventional models that HP would have sold you at the same time, even if it doesn’t give the same THD figure you might have been looking for.

If distortion interests you, it’s a subject we’ve looked at in the past.

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Bluetoothing Beautiful Phones

You’ve seen a landline phone converted into a Bluetooth headset. There’s nothing new there. It’s great for confusing kids when asking them to dial a rotary phone, but that’s about it. It’s the same phone, built by Ma Bell for fifty years, converted with a little Bluetooth breakout board.

You’ve never seen a landline conversion like this. This is [Alessandro]’s Bluetooth-converted Beocom 600, complete with a drop-in replacement circuit board that turns this beautiful Bang & Olufsen design into a useful device for the smartphone era.

This phone was designed as Bang & Olufsen’s entry into phone design, and we’re shocked, simply shocked, that Apple hasn’t tried to lift this design yet. Unfortunately, it’s designed for landlines, making it horrifically inconvenient to take to Starbucks. That’s where the Bluetooth comes in, and [Alessandro]’s custom board that is meant to replace the guts of this vintage phone. Honestly, with Bluetooth modules it’s probably easier to deal with that instead of a telephone line.

Right now, the work is concentrated on the user interface, which means taking apart and mapping the pinout of the buttons. This keypad is plastic over rubber domes contacting a polyester sheet with contacts, feeding out to a ribbon cable. It’s fantastic work and finally some of the best design out there will be brought into the modern era.

Bringing A Century Stereo Into The 21st Century

Way back in the previous century, people used to use magnetized strips of tape to play music. It might be hard to believe in today’s digital world, but these “cassette” tapes were once all the rage. [Steve] aka [pinter75] recently found a Bang & Olufsen stereo with this exact type of antequated audio playback device, and decided to upgrade it with something a little more modern.

Once the unit arrived from eBay and got an electronic tune-up, [pinter75] grabbed a Galaxy S3 out of his parts drawer and got to work installing it in the old cassette deck location. He used a laser cutter to make a faceplate for the phone so it could be easily installed (and removed if he decides to put the tape deck back in the future).

The next step was wiring up power and soldering the audio output directly to the AUX pins on the stereo. Once everything was buttoned up [pinter75] found that everything worked perfectly, and mounted the stereo prominently on his wall. It’s always great when equipment like this is upgraded and repaired rather than thrown out.

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Hackaday Links: April 19, 2015

Bang & Olufsen have made some pretty amazing equipment for a long, long time. That last part can become a problem. [Oliver] found the electrolytic caps on his Beomaster 2400 were causing problems. He completely recapped the unit, all the electrolytics anyway, and the pictures of the process are nothing short of eye-candy.

The closure of the Bacman forums marks the end of an era. For years this has been among the top (okay, it’s definitely been the top one but we don’t want to start a flamewar) sites for handheld and console modding. Here’s just one random example of the many projects we covered from that community (note that main link is now sadly 404). The closure message cites the near-absolute death of modding. We haven’t thought about it much, but these mods were futuristic. Then smartphones.

Fans of How It’s Made and 3D printing will want to tune in on April 30th at 9pm EST. The show does a fantastic job of showing off the amazing story behind how all the stuff in our lives comes to be visited LulzBot in Loveland, Colorado for a segment on the manufacturing process of a 3D printer.

We’re not sure why we didn’t lead with this: All celebrate, for humanity is saved! The secret behind getting something out of nothing has been discovered. This reactionless generator has been tested at efficiencies as high as 250%. We’re working on a way to bottle all that extra juice and sell it at outrageous prices.

The thing about free energy is that you become dependent on it. What if the laws of physics return from vacation and the thing stops working? Then you have a robot apocalypse with all kinds of hidden messages and puzzles in it.